Temperature-responsive flow rate control devices for liquid metal systems are useful in a number of different technological areas. For example, such a control device can be employed in a solar collector where sunlight is concentrated upon a small sodium-cooled collector. The device throttles the flow to assure a constant high temperature reservoir with varying atmospheric conditions and changing sun angle. Employment of constant temperature reservoirs would allow optimum design of heat exchangers. Because low efficiencies are characteristic of solar devices, even small increases in heat exchanger performance would have a sizable overall system effect.
In addition, such a device is useful to control the exit temperature of Liquid Metal Fast Breeder Reactor (LMFBR) blanket assemblies. In an LMFBR there is a power shift from core to blanket during each fuel cycle due to burnup of fissionable material in the core and production of fissionable material in the blanket. Power changes of at least a factor of two are predicted for individual blanket assemblies during a single fuel cycle. Also fuel assemblies produce less power as they age due to burnup. Providing the blanket assemblies with variable orifices would make it possible to divert some of the fuel coolant to the blanket assemblies and thus also stabilize fuel assembly temperatures.